If \({\mathsf {K}}_i\in {\mathcal {Q}}_{\varepsilon , \delta }\)  for \(i\in [n]\) , then we have \(\eta _{e^\varepsilon }({\mathsf {K}}_i) \le \delta \) . According to (REF ), it thus leads to
\(\eta _{\mathsf {TV}}({\mathsf {K}}_i)\le \varphi (\varepsilon , \delta )\) .
Invoking [1]} (see also [2]} and [3]}), we obtain
\(\eta _{\mathsf {TV}}(P_{Z^n|X^n})&\le \max _{i\in [n]}\left[1-(1-\eta _{{\mathsf {TV}}}({\mathsf {K}}_i))^n\right]\\&\le \left[1-(1-\varphi (\varepsilon , \delta ))^n\right]\\& = \varphi _n(\varepsilon , \delta ).\) 
